From a35b9dfc80338cf2049c75b0f4af22776001d5d3 Mon Sep 17 00:00:00 2001
From: Steve Arnold <nerdboy@gentoo.org>
Date: Fri, 15 Dec 2017 16:43:22 -0800
Subject: [PATCH] ARM: dts,driver: imx6,udooqdl: add arduino manager driver and
 update dts

* note this is required to upload sketches to sam3 from arduino IDE

Signed-off-by: Steve Arnold <nerdboy@gentoo.org>
---
 arch/arm/boot/dts/imx6qdl-udoo.dtsi |  20 ++
 drivers/misc/Kconfig                |   7 +
 drivers/misc/Makefile               |   1 +
 drivers/misc/udoo_ard.c             | 417 ++++++++++++++++++++++++++++++++++++
 4 files changed, 445 insertions(+)
 create mode 100755 drivers/misc/udoo_ard.c

diff --git a/arch/arm/boot/dts/imx6qdl-udoo.dtsi b/arch/arm/boot/dts/imx6qdl-udoo.dtsi
index e28f90005130..fd404d3299a5 100644
--- a/arch/arm/boot/dts/imx6qdl-udoo.dtsi
+++ b/arch/arm/boot/dts/imx6qdl-udoo.dtsi
@@ -89,6 +89,17 @@
 		mux-int-port = <1>;
 		mux-ext-port = <6>;
 	};
+
+	udoo_ard: udoo_ard_manager {
+		compatible = "udoo,imx6q-udoo-ard";
+		pinctrl-names = "default";
+		pinctrl-0 = <&pinctrl_udooard>;
+		bossac-clk-gpio   = <&gpio6 3 0>;
+		bossac-dat-gpio   = <&gpio5 18 0>;
+		bossac-erase-gpio = <&gpio4 21 0>;
+		bossac-reset-gpio = <&gpio1 0 0>;
+		status = "okay";
+	};
 };
 
 &fec {
@@ -200,6 +211,15 @@
 			>;
 		};
 
+		pinctrl_udooard: udooardgrp {
+			fsl,pins = <
+			MX6QDL_PAD_DISP0_DAT0__GPIO4_IO21       0x80000000
+			MX6QDL_PAD_CSI0_DAT17__GPIO6_IO03       0x80000000
+			MX6QDL_PAD_CSI0_PIXCLK__GPIO5_IO18      0x80000000
+			MX6QDL_PAD_GPIO_0__GPIO1_IO00           0x80000000
+			>;
+		};
+
 		pinctrl_usdhc3: usdhc3grp {
 			fsl,pins = <
 				MX6QDL_PAD_SD3_CMD__SD3_CMD		0x17059
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index f1c4c891cda3..afd54fdc983d 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -536,6 +536,13 @@ config TIEQEP
 	  To compile this driver as a module, choose M here: the module
 	  will be called tieqep.
 
+config UDOO_ARD
+	tristate "UDOO-Arduino erase/reset Driver"
+	default y
+	help
+	  This driver is used to erase and reset arduino board via command sent
+	  over USB-to-SERIAL connection.
+
 source "drivers/misc/c2port/Kconfig"
 source "drivers/misc/eeprom/Kconfig"
 source "drivers/misc/cb710/Kconfig"
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index 3225f1e37dfc..b68828f424c4 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -57,6 +57,7 @@ obj-y				+= cape/
 obj-$(CONFIG_ECHO)		+= echo/
 obj-$(CONFIG_VEXPRESS_SYSCFG)	+= vexpress-syscfg.o
 obj-$(CONFIG_CXL_BASE)		+= cxl/
+obj-$(CONFIG_UDOO_ARD)		+= udoo_ard.o
 obj-$(CONFIG_ASPEED_LPC_CTRL)	+= aspeed-lpc-ctrl.o
 obj-$(CONFIG_ASPEED_LPC_SNOOP)	+= aspeed-lpc-snoop.o
 obj-$(CONFIG_PCI_ENDPOINT_TEST)	+= pci_endpoint_test.o
diff --git a/drivers/misc/udoo_ard.c b/drivers/misc/udoo_ard.c
new file mode 100755
index 000000000000..2210738e09c0
--- /dev/null
+++ b/drivers/misc/udoo_ard.c
@@ -0,0 +1,417 @@
+/*
+ * udoo_ard.c
+ * UDOO quad/dual Arduino flash erase / CPU resetter
+ *
+ * Copyright (C) 2013-2015 Aidilab srl
+ * Author: UDOO Team <social@udoo.org>
+ * Author: Giuseppe Pagano <giuseppe.pagano@seco.com>
+ * Author: Francesco Montefoschi <francesco.monte@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/errno.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/delay.h>
+#include <linux/gpio.h>
+#include <linux/sched.h>
+#include <linux/sched/clock.h>
+#include <linux/kernel.h>
+#include <linux/workqueue.h>
+#include <linux/fs.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_gpio.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+#include <linux/uaccess.h>
+
+#define DRIVER_NAME              "udoo_ard"
+#define PINCTRL_DEFAULT          "default"
+#define AUTH_TOKEN               0x5A5A
+#define MAX_MSEC_SINCE_LAST_IRQ  400
+#define GRAY_TIME_BETWEEN_RESET  10000 // In this time we can't accept new erase/reset code
+
+static struct workqueue_struct *erase_reset_wq;
+typedef struct {
+    struct work_struct erase_reset_work;
+    struct pinctrl *pinctrl;
+    struct pinctrl_state *pins_default;
+    int    step;
+    int    cmdcode;
+    int    erase_reset_lock;
+    int    gpio_bossac_clk;
+    int    gpio_bossac_dat;
+    int    gpio_ard_erase;
+    int    gpio_ard_reset;
+    unsigned long    last_int_time_in_ns;
+    unsigned long    last_int_time_in_sec;
+} erase_reset_work_t;
+
+erase_reset_work_t *work;
+static u32 origTX, origRX; // original UART4 TX/RX pad control registers
+static int major; // for /dev/udoo_ard
+static struct class *udoo_class;
+
+static struct platform_device_id udoo_ard_devtype[] = {
+    {
+        /* keep it for coldfire */
+        .name = DRIVER_NAME,
+        .driver_data = 0,
+    }, {
+        /* sentinel */
+    }
+};
+MODULE_DEVICE_TABLE(platform, udoo_ard_devtype);
+
+static const struct of_device_id udoo_ard_dt_ids[] = {
+    { .compatible = "udoo,imx6q-udoo-ard", .data = &udoo_ard_devtype[0], },
+    { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, udoo_ard_dt_ids);
+
+static void disable_serial(void)
+{
+    u32 addrTX;
+    void __iomem *_addrTX;
+
+    printk("[bossac] Disable UART4 serial port.\n");
+
+    addrTX = 0x20E01F8;
+    _addrTX = ioremap(addrTX, 8);
+
+    origTX = __raw_readl(_addrTX);
+    origRX = __raw_readl(_addrTX + 0x4);
+
+    __raw_writel(0x15, _addrTX);
+    __raw_writel(0x15, _addrTX + 0x4);
+
+    iounmap(_addrTX);
+}
+
+static void enable_serial(void)
+{
+    u32 addrTX;
+    void __iomem *_addrTX;
+
+    printk("[bossac] Enable UART4 serial port.\n");
+
+    addrTX = 0x20E01F8;
+    _addrTX = ioremap(addrTX, 8);
+
+    __raw_writel(origTX, _addrTX);
+    __raw_writel(origRX, _addrTX + 0x4);
+
+    iounmap(_addrTX);
+}
+
+static void erase_reset(void)
+{
+    printk("[bossac] UDOO ERASE and RESET on Sam3x started.\n");
+
+    gpio_direction_input(work->gpio_ard_erase);
+    gpio_set_value(work->gpio_ard_reset, 1);
+    msleep(1);
+
+    gpio_direction_output(work->gpio_ard_erase, 1);
+    msleep(300);
+    gpio_direction_input(work->gpio_ard_erase);
+
+    msleep(10);
+    gpio_set_value(work->gpio_ard_reset, 0);
+
+    msleep(80);
+    gpio_set_value(work->gpio_ard_reset, 1);
+
+    printk("[bossac] UDOO ERASE and RESET on Sam3x EXECUTED.\n");
+}
+
+static void shutdown_sam3x(void)
+{
+    printk("[bossac] RESET on Sam3x.\n");
+
+    gpio_set_value(work->gpio_ard_reset, 0);
+}
+
+static void erase_reset_wq_function( struct work_struct *work2)
+{
+    disable_serial();
+    erase_reset();
+    msleep(GRAY_TIME_BETWEEN_RESET);
+
+    work->erase_reset_lock = 0;
+}
+
+/*
+ * Called everytime the gpio_bossac_clk signal toggles.
+ * If the auth token (16 bit) is found, we look for the command code (4 bit).
+ * The code 0x0F is sent by Bossac to trigger an erase/reset (to achieve this,
+ * erase_reset_wq is scheduled). Before starting to program the flash, we disable
+ * the UART4 serial port, otherwise there is too noise on the serial lines (the
+ * programming port and UART4 port are connected together, see hw schematics).
+ * When Bossac finishes to flash/verify, the code 0x00 is sent which re-enables
+ * the UART4 port.
+ */
+static irqreturn_t udoo_bossac_req(int irq, void *dev_id)
+{
+    int retval, auth_bit, expected_bit, msec_since_last_irq;
+    u64 nowsec;
+    unsigned long rem_nsec;
+    erase_reset_work_t *erase_reset_work;
+
+    auth_bit = 0;
+    if (gpio_get_value(work->gpio_bossac_dat) != 0x0) {
+        auth_bit = 1;
+    }
+
+    erase_reset_work = (erase_reset_work_t *)work;
+
+    nowsec = local_clock();
+    rem_nsec = do_div(nowsec, 1000000000) ;
+    msec_since_last_irq = (((unsigned long)nowsec * 1000) + rem_nsec/1000000 ) - (((unsigned long)erase_reset_work->last_int_time_in_sec * 1000) + erase_reset_work->last_int_time_in_ns/1000000);
+
+    if (msec_since_last_irq > MAX_MSEC_SINCE_LAST_IRQ) {
+        erase_reset_work->step = 0;
+#ifdef DEBUG
+        printk("[bossac] Reset authentication timeout!\n");
+#endif
+    }
+
+#ifdef DEBUG
+    printk("[bossac] STEP %d -> 0x%d \n", erase_reset_work->step, auth_bit);
+#endif
+    erase_reset_work->last_int_time_in_ns = rem_nsec;
+    erase_reset_work->last_int_time_in_sec = nowsec;
+
+    if ( erase_reset_work->step < 16 ) {  // Authenticating received token bit.
+        expected_bit = (( AUTH_TOKEN >> erase_reset_work->step ) & 0x01 );
+        if ( auth_bit == expected_bit ) {
+            erase_reset_work->step = erase_reset_work->step + 1;
+        } else {
+            erase_reset_work->step = 0;
+        }
+    } else { // Passed all authentication step. Receiving command code.
+        erase_reset_work->cmdcode = erase_reset_work->cmdcode | (auth_bit << (erase_reset_work->step - 16));
+        erase_reset_work->step = erase_reset_work->step + 1;
+    }
+
+#ifdef DEBUG
+    printk("erase_reset_work->erase_reset_lock = %d \n", erase_reset_work->erase_reset_lock);
+#endif
+    if ( erase_reset_work->step == 20 ) {  // Passed authentication and code acquiring step.
+#ifdef DEBUG
+        printk("[bossac] Received code = 0x%04x \n", erase_reset_work->cmdcode);
+#endif
+        if (erase_reset_work->cmdcode == 0xF) {
+            if (erase_reset_work->erase_reset_lock == 0) {
+		erase_reset_work->erase_reset_lock = 1;
+		retval = queue_work( erase_reset_wq, (struct work_struct *)work );
+            } else {
+#ifdef DEBUG
+                printk("Erase and reset operation already in progress. Do nothing.\n");
+#endif
+            }
+        } else {
+            enable_serial();
+        }
+        erase_reset_work->step = 0;
+        erase_reset_work->cmdcode = 0;
+    }
+
+    return IRQ_HANDLED;
+}
+
+/*
+ * Takes control of clock, data, erase, reset GPIOs.
+ */
+static int gpio_setup(void)
+{
+    int ret;
+
+    ret = gpio_request(work->gpio_bossac_clk, "BOSSA_CLK");
+    if (ret) {
+        printk(KERN_ERR "request BOSSA_CLK IRQ\n");
+        return -1;
+    } else {
+        gpio_direction_input(work->gpio_bossac_clk);
+    }
+
+    ret = gpio_request(work->gpio_bossac_dat, "BOSSA_DAT");
+    if (ret) {
+        printk(KERN_ERR "request BOSSA_DAT IRQ\n");
+        return -1;
+    } else {
+        gpio_direction_input(work->gpio_bossac_dat);
+    }
+
+    ret = gpio_request(work->gpio_ard_erase, "BOSSAC");
+    if (ret) {
+        printk(KERN_ERR "request GPIO FOR ARDUINO ERASE\n");
+        return -1;
+    } else {
+        gpio_direction_input(work->gpio_ard_erase);
+    }
+
+    ret = gpio_request(work->gpio_ard_reset, "BOSSAC");
+    if (ret) {
+        printk(KERN_ERR "request GPIO FOR ARDUINO RESET\n");
+        return -1;
+    } else {
+        gpio_direction_output(work->gpio_ard_reset, 1);
+    }
+
+    return 0;
+}
+
+static ssize_t device_write(struct file *filp, const char *buff, size_t len, loff_t *off)
+{
+    char msg[10];
+    long res;
+
+    if (len > 10)
+		return -EINVAL;
+
+
+	res = copy_from_user(msg, buff, len);
+    if (res) {
+        return -EFAULT;
+    }
+	msg[len] = '\0';
+
+    if (strcmp(msg, "erase")==0) {
+        erase_reset();
+    } else if (strcmp(msg, "shutdown")==0) {
+        shutdown_sam3x();
+    } else if (strcmp(msg, "uartoff")==0) {
+        disable_serial();
+    } else if (strcmp(msg, "uarton")==0) {
+        enable_serial();
+    } else {
+        printk("[bossac] udoo_ard invalid operation! %s", msg);
+    }
+
+	return len;
+}
+
+static struct file_operations fops = {
+    .write = device_write,
+};
+
+/*
+ * If a fdt udoo_ard entry is found, we register an IRQ on bossac clock line
+ * and we create /dev/udoo_ard
+ */
+static int udoo_ard_probe(struct platform_device *pdev)
+{
+    int retval;
+    struct device *temp_class;
+    struct platform_device *bdev;
+    struct device_node *np;
+
+    bdev = kzalloc(sizeof(*bdev), GFP_KERNEL);
+    np = pdev->dev.of_node;
+
+    if (!np)
+            return -ENODEV;
+
+    work = (erase_reset_work_t *)kmalloc(sizeof(erase_reset_work_t), GFP_KERNEL);
+    if (work) {
+	    work->gpio_ard_reset = of_get_named_gpio(np, "bossac-reset-gpio", 0);
+	    work->gpio_ard_erase = of_get_named_gpio(np, "bossac-erase-gpio", 0);
+	    work->gpio_bossac_clk = of_get_named_gpio(np, "bossac-clk-gpio", 0);
+	    work->gpio_bossac_dat = of_get_named_gpio(np, "bossac-dat-gpio", 0);
+	    work->pinctrl = devm_pinctrl_get(&pdev->dev);
+        work->pins_default = pinctrl_lookup_state(work->pinctrl, PINCTRL_DEFAULT);
+    } else {
+	    printk("[bossac] Failed to allocate data structure.");
+	    return -ENOMEM;
+    }
+
+    pinctrl_select_state(work->pinctrl, work->pins_default);
+    gpio_setup();
+
+    printk("[bossac] Registering IRQ %d for BOSSAC Arduino erase/reset operation\n", gpio_to_irq(work->gpio_bossac_clk));
+    retval = request_irq(gpio_to_irq(work->gpio_bossac_clk), udoo_bossac_req, IRQF_TRIGGER_FALLING, "UDOO", bdev);
+
+    major = register_chrdev(major, "udoo_ard", &fops);
+    if (major < 0) {
+		printk(KERN_ERR "[bossac] Cannot get major for UDOO Ard\n");
+		return -EBUSY;
+	}
+
+    udoo_class = class_create(THIS_MODULE, "udoo_ard");
+	if (IS_ERR(udoo_class)) {
+		return PTR_ERR(udoo_class);
+	}
+
+	temp_class = device_create(udoo_class, NULL, MKDEV(major, 0), NULL, "udoo_ard");
+	if (IS_ERR(temp_class)) {
+		return PTR_ERR(temp_class);
+	}
+
+    printk("[bossac] Created device file /dev/udoo_ard\n");
+
+    erase_reset_wq = create_workqueue("erase_reset_queue");
+    if (erase_reset_wq) {
+
+        /* Queue some work (item 1) */
+        if (work) {
+            INIT_WORK( (struct work_struct *)work, erase_reset_wq_function );
+            work->step = 1;
+            work->cmdcode = 0;
+            work->last_int_time_in_ns = 0;
+            work->last_int_time_in_sec = 0;
+            work->erase_reset_lock = 0;
+            //  retval = queue_work( erase_reset_wq, (struct work_struct *)work );
+        }
+    }
+    return  0;
+}
+
+static int udoo_ard_remove(struct platform_device *pdev)
+{
+    printk("[bossac] Unloading UDOO ard driver.\n");
+    free_irq(gpio_to_irq(work->gpio_bossac_clk), NULL);
+
+    gpio_free(work->gpio_ard_reset);
+    gpio_free(work->gpio_ard_erase);
+    gpio_free(work->gpio_bossac_clk);
+    gpio_free(work->gpio_bossac_dat);
+
+    device_destroy(udoo_class, MKDEV(major, 0));
+    class_destroy(udoo_class);
+    unregister_chrdev(major, "udoo_ard");
+
+    return 0;
+}
+
+static struct platform_driver udoo_ard_driver = {
+    .driver = {
+        .name   = DRIVER_NAME,
+        .owner  = THIS_MODULE,
+        .of_match_table = udoo_ard_dt_ids,
+    },
+    .id_table = udoo_ard_devtype,
+    .probe  = udoo_ard_probe,
+    .remove = udoo_ard_remove,
+};
+
+module_platform_driver(udoo_ard_driver);
+
+MODULE_ALIAS("platform:"DRIVER_NAME);
+MODULE_LICENSE("GPL");
-- 
2.15.0

